<style>
  .mercury-select {
    position: absolute;
    height: 100px;
    width: 100px;
  }
  #button {
    position: absolute;
    top: 42px;
    left: 42px;
    width: 20px;
    height: 20px;
  }
</style>
<div id="select_container"></div>
<div id="button"></div>